Electrophotographic photosensitive member containing a nitrocellulose-polyvinyl pyrrolidone barrier layer

ABSTRACT

An electrophotographic photosensitive member comprises a support, a barrier layer overlying the support, the barrier layer comprising a composite of nitrocellulose and polyvinylpyrrolidone, and an organic photoconductive layer overlying the barrier.

United States Patent [191 Matsuno et al.

[45] Oct. 1,1974

[ ELECTROPl-IOTOGRAPl-IIC PHOTOSENSITIVE MEMBER CONTAINING ANITROCELLULOSE-POLYVINYL PYRROLIDONE BARRIER LAYER [75] Inventors:I-Iiroshi Matsuno, Tokyo; Ichiro Endo, Kawasaki; Kiyoshi Suzki, Tokyo,all of Japan [73] Assignee: Canon Kabushiki Kaisha, Tokyo,

Japan [22] Filed: June 19, 1972 [21] Appl. No.: 264,334

[30] Foreign Application Priority Data June 22, 1971 Japan 46-44998 [52]US. Cl. ..96/1.5, 117/218 [51] Int. Cl. G03g 5/00, 603g 5/02 [58] Fieldof Search 96/15, 1.8; 117/218; 162/138 [56] References Cited UNITEDSTATES PATENTS 3,245,833 4/1966 Trevoy 117/201 OTHER PUBLICATIONSChadwell et al., Barrier Layer Suitable For Accept- I ing DichroicSensitizer Particles, IBM Technical Disclosure Bulletin, Vol. 14, N0. 5,Oct. 1971, Pg. 1509.

Primary Examiner-David Klein Assistant Examiner-John R. Miller [5 7ABSTRACT An electrophotographic photosensitive member comprises asupport, a barrier layer overlying the support, the barrier layercomprising a composite of nitrocellulose and polyvinylpyrrolidone, andan organic photoconductive layer overlying the barrier.

3 Claims, No Drawings ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MEMBERCONTAINING A NITROCELLULOSE-POLYVINYL PYRROLIDONE BARRIER LAYERBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to an electrophotographic photosensitive member utilizing anorganic photoconductive material.

2. Description of the Prior Art Heretofore, there have been knownvarious organic photoconductive materials forming high polymers or oflow molecular weight such as poly-N-vinylcarbazole, brominatedpoly-N-vinylcarbazole, polyvinylanthracene, oxadiazoles, andacylhydrazones. If desired, sensitizers may be added to the organicphotoconductors to produce electrophotographic photosensitive members.

Organic photoconductive materials are excellent in points oftransparency, flexibility, selectivity of charging polarity and surfacesmoothness. Particularly, high polymer organic photoconductive materialshave film-shapeability.

However, a photosensitive member composed of an organic photoconductivematerial merely overlying a conductive support is not satisfactory toelectrophotographic application since electrostatic problems arise.

In other words, an electrophotographic photosensitive member comprisinga conventional organic photoconductive material is often broken byspontaneous discharge after charging by corona discharging and thedeveloped image contains white points which remarkably reduce the imagequality.

For the purpose of solving such a drawback, it was proposed to provide aresin adhesive layer between an organic photoconductive layer and asupport; However there does not yet exist a resin adhesive layer whichdoes not reduce the sensitivity of a photosensitive layer and cansufficiently prevent discharging destroy.

In electrophotographic processes in which a photosensitive member isrepeatedly used, there are various drawbacks, that is, fatigue phenomenasuch as lowering of charge amount, low uprising of charging, residualcharge retention and loweringof sensitivity as well as dischargedistruction.

Heretofore, it has been studied to apply a photosensitive membercomprising an organic photoconductive material to an electrophotographicprocess using a photosensitive member repeatedly in charging, exposing,developing and transferring steps. Neither the above mentioned problemis recognized.

A photosensitive member comprising a support and a photosensitive layercomposed of ZnO-binder resin, and a barrier layer being providedtherebetween is known, but a photosensitive member comprising a supportand an organic photoconductive material, and a barrier layer beingprovided therebetween, is impractical. Practically effective barriermaterials have not yet been found.

The present inventors have found particular barrier materials capable ofpreventing both discharge destruction and fatigue of a photosensitivemember used for electrophotographic processes using the photosensitivemember repeatedly.

SUMMARY OF THE INVENTION In accordance with the present invention, thereis provided an electrophotographic photosensitive member which comprisesa support, a barrier layer overlying the support and comprising acomposite of nitrocellulose and polyvinylpyrrolidone, and an organicphotoconductive layer overlying the barrier layer.

It is an object of this invention to provide an electrophotographicphotosensitive member free from discharge destruction and causingfatigue phenomenon only to a less extent upon repeating use.

. DESCRIPTION OF THE PREFERRED EMBODIMENTS Barrier layers used in thisinvention are to be selected in such a manner that the volumeresistivity are of a certain appropriate values so as to completelyprevent a discharge destruction and in a photosensitive member usedrepeatedly the fatigue phenomenon is prevented and the barrier does notdisadvantageously effect the electrophotographic characteristics such asphotosensitivity.

Barrier layer materials satisfying such requisites are a composite ofnitrocellulose and polyvinylpyrrolidone.

There are various nitrocelluloses having various degrees ofpolymerization and degrees of nitration. These nitrocelluloses may beused for the present invention.

Providing such a barrier between an organic photoconductive layer and asupport serves to prevent discharge destruction of the resultingphotosensitive member and fatigue of the photosensitive member uponrepeated use of the photosensitive member. Furthermore, such a barrierlayer enables one to produce an electrophotographic photosensitivemember having an electrophotosensitive layer of excellent filmcharacteristics such as adhesivity, flexibility, tensile strength,stable performance and the like.

As a support used in this invention, there may be used variousconventional supports used for electrophotographic photosensitivemember. Representative supports are metal plates such as aluminum,copper and the like; paper; aluminum laminate paper; synthetic resinfilm containing surfactant; synthetic resin film treated with aquaternary ammonium salt for imparting conductivity; and glass, paper,and synthetic resin on which metal, metal oxide or metal halide isvapor-deposited. In general, surface resistivity is preferably less than10 ohm and more preferably less than 10 ohm.

The barrier layer' is formed on the support in such a manner that thebarrier material such as nitrocellulose and in an appropriate solvent ata ratio of from 2 8 to 8 2 by weight, and the viscosity is adjusted tosuch a value that is suitable for coating and the resulting solution iscoated on the support according to conventional coating methods followedby drying such as air drying and heat drying to form a barrier layer.

Further, since the barrier layer composed of a composite ofnitrocellulose and polyvinylpyrrolidone has a good flexibility, noplasticizer is necessary in preparing a coating solution, butfilm-shapeability may be more improved by adding 10 to 50 percent ofgood compatible plasticizer (for example, trichloroethylphosphate,

The film of the resulting barrier layer is soft and strong. and hassufficient flexibility.

Depending upon the purpose of the barrier layer. pigments and otheradditives may be added in a necessary amount to a coating solution forproducing the barrier layer.

The film thickness about the barrier layer is preferably less than aboutmicrons, more preferably, 3 to 7 microns. Particularly, in aphotosensitive plate for -a master a good result was obtained even whenthe film thickness of the barrier layer is about 1 micron. When thethickness of the barrier layer is thicker than 10 microns, someexperiments show that the electrophotographic sensitivity is adverselyaffected. When the barrier layer is less than 10 microns thick, there isa hardly recognizable lowering of sensitivity and when the barrier layeris thicker than 3 microns thick, discharge destruction and fatiguephenomenon upon repeated use of the photosensitive member can beprevented.

An organic photoconductive layer is formed on the barrier layeraccording to conventional methods to produce an electrophotographicphotosensitive member of this invention.

As the organic photoconductive materials, there may be used knownorganic photoconductive material. Particularly preferable materials areorganic polymeric photoconductive materials such as poly-N-vinylcarbazole, chlorinated poly-N-vinylcarbazole, brominatedpoly-N-vinylcarbazole, cyanated poly-N- vinylcarbazole,polyvinylacenaphthene and the like.

Chlorinated poly-N-vinylcarbazole may be obtained by chlorinatingpoly-N-vinylcarbazole with chlorine gas or sulfuryl chloride, or bypolymerizing a chlorinated vinylcarbazole. Detailed preparation methodsare disclosed in German Offenlegungsschrift 2035679.

The following examples are given for illustrating the present invention,but not for restriction thereof. Example 1 An aqueous solution of anagent for lowering resistance poly-(N,N-dimethyl-3, S-methylene)piperidinium chloride was coated on a polyethyleneterephthalate filmhaving an undercoating layer (75 microns thick) and dried to form atransparent conductive layer. Then, a 10 percent (by weight) solution ofnitrocellulose (RS-2, trade name, supplied by Daiseru, degree ofnitration of 11.5 to 12.2 percent) was mixed with a 10 percent solutionof polyvinylpyrrolidone (PBP-K90, trade name, supplied by GAF Co.) at aratio of 2:8 (by weight). Solvents in both solutions above areethylalcohol-methylalcohol (7:3).

Methyl ethyl ketone was added, in an amount of one half of the mixture,to said mixture to obtain a coating solution of a barrier layer.

The solution thus obtained was coated on the transparent conductivelayer at thickness of 3 to 4 microns (when dried) and dried to form abarrier layer. The resulting coating film (barrier layer) was highlytransparent, strong and flexible and tightly adhered to the conductivelayer. Further, on the barrier layer was coated a photosensitive agentcomposed of poly-N- vinylcarbazole, Crystal Violet, andbenzenechlorobenzene (1:1) at 8 g./m. and dried to form a photosensitivelayer. The resulting transparent organic photoconductive film wassubjected to a known electrophotographic reproduction procedure, thatis, charging, ex-

posing, reduction photographing. and wet-developing to form an excellentpositive images. When the positive images were enlarged by a projector.it was found that the film was free from various electrostatic troubleand gave clear and sharp projected images. On the contrary, when aconventional photosensitive member having no barrier layer was used,there were formed considerable white points caused by discharge destroy.

Example 2 On a conductive support composed of polyester film (75 micronsthick) having an aluminum vapor deposited layer of visible raytransmitting rate of percent there was coated a mixture obtained bymixing a 5 percent solution of nitrocellulose (RS 20, trade name,supplied by Daiseru, degree of nitration of 11.5 to 12.2 percent) with a10 percent solution of polyvinylpyrrolidone (PEP-K90, trade name,supplied by GAF Co.) both in ethylalcohol-methylalcohol (7:3) at a ratioof 1:1 (by weight) and adding thereto methyl ethyl ketone anddimethylformamide, each amount of which is one fourth the weight of theabove mixture, at 3 to 4 microns thick (when dried) to form a barrierlayer and dried. The resulting barrier layer showed excellent propertiessimilar to Example 1. A solution composed of chlorinatedpoly-N-vinylcarbazole 3 g., N- vinylcarbazole 0.1 g., carbontetrabromide 0.2 g., and 45 ml. of a mixed solvent ofbenzene-chlorobenzene (1:1) was irradiated by ultraviolet rays for 20minutes, stored in a dark place for 6 hours at ambient temperature andcoated on the barrier layer. The resulting transparent organicphotoconductive film was treated in a way similar to Example 1. Thus,there was obtained excellent transparent positive images free from whitepoints.

Example 3 On a conductor composedof polyester film microns thick) havingan aluminum vapor deposited layer of visible ray transmitting rate of 60percent there was coated a mixture solution which was obtained by insuch a way that a 15 percent solution of nitrocellulose (RS /2, tradename, supplied by Daiseru, degree of nitration of 1 1.5 to 12.2 percent)in ethylalcoholmethylalcohol (7:3) was mixed with a 15 percent solutionof polyvinylpyrrolidone (PBP-K60, trade name, supplied by GAF Co.) inethylalcoholmethylalcohol (7:3) at ratio of 8:2 (by weight), and amountsof methyl ethyl ketone and dimethylformamide amount one fourth the abovemixture by weight, respectively, was added to said mixture, and 30percent of trichloroethyl phosphate was added, at thickness of 4 to 5microns (when dried) to form a barrier layer. As shown in Example l, theresulting barrier layer was transparent, strong, flexible and highlyadhesive to the deposited layer.

On the barrier layer there was coated a photosensitive agent composed ofa solution of chlorinated poly- N-vinylcarbazole and Rhodamine B inbenzenechlorobenzene (1:1) at 5 to 6 g./m. and dried to produce aphotosensitive layer.

The resulting photosensitive film was photographically reduced, in a waysimilar to Example 1, to prduce sharp positive images. The sensitivitywas good. When the resulting positive images were enlarged with aprojector, there were obtained projected images free from white pointsand of high fidelity to an original pattern. The film was strong,flexible and highly adhesive.

Example 4 On a baryta paper subjected to a treatment for impartingconductivity there was coated, in to microns thick (when dried), amixture solution which was obtained by such a way that a 10 percentsolution of nitrocellulose (RS-l, trade name, supplied by Daiseru,degree of nitration of 11.5 to 12.2 percent) inethylalcohol-methylalcohol (7:3) was mixed with a 10 percent (by weight)solution of polyvinylpyrrolidone (PBP- K90, trade name, supplied by GAECo.) in ethylalcohol-methylalcohol (7:3) at ratio of 2:8 (by weight) andan amount of methyl ethyl ketone which is one and a half the amount ofthe above mixture by weight was added to said mixture to form a barrierlayer and dried.

Further, on the resulting barrier layer there was coated aphotosensitive agent composed of poly-N- vinylcarbazole and CrystalViolet in benzenechlorobenzene (1:1) at 4 to 6 g./m. and dried.

The resulting photosensitive film was charged, exposed, and developedaccording to a conventional electrophotographic reproducing method toform clear visible images free from white points.

Example 5 On an aluminum plate (31 microns thick), conductive support,there was coated a mixture solution obtained in such a way that a 10percent solution of nitrocellulose (RS 2, trade name, supplied byDaiseru, degree of nitration of 11.5 to 12.2 percent) was mixed with a10 percent solution of polyvinylpyrrolidone (PBP-K90, trade name,supplied by GAF Co.) at ratio of 1:1 (by weight) both inethylalcohol-methylalcohol (7:3 and amounts of methyl ethyl ketone anddimethylformamide each of which is one fourth the above mixture byweight, respectively was added to said mixture, at l to 2 microns thick(when dried) to form a barrier layer and dried. The resulting barrierlayer was highly transparent, strong and flexible, and tightly adheredto the aluminum support. On the barrier layer there was coated aphotosensitive agent composed of poly-N-vinylcarbazole 2 g., Rhodamine B20 mg. and diphenyl chloride (Kanechlor, trade name, supplied byKanegafuchi Kagaku Co.) as plasticizer in 40 ml. ofbenzene-chlorobenzene 1:1 to form a photosensitive layer of 9 micronsthick. For the purpose of using as a master for electrophotography theresulting photosensitive plate was repeatedly subjected to anelectrophotographic process which comprises corona-charging at 7.0 KV,exposing to a 500 W tungsten lamp at 40 lux. sec. and transferring theresulting electrostatic image to an electrostatic recording paper. Whenthe electrostatic recording paper was developed with a liquid developer,the resulting image was excellent, and the effect of preventingdischarge destroy was far better than conventional master having nobarrier layer. The durable repeating number (the number of cycles that aphotosensitive member may be sequentially charged, exposed, developed(if required) and transferred as a master for electrophotography withoutexhibiting fatigue phenomena) was as shown below.

Having no barrier about 100 times Having a barrier about 1500 timesExample 6 A photosensitive plate prepared in a way similar to Example 5was repeatedly subjected to a conventional xerographic processcomprising charging at -7.0 KV, exposing a light pattern at about 100lux. sec., developing with a liquid developer, transferring to anordinary paper and cleaning the photosensitive plate. The sensitivitywas excellent and the discharge destruction effect by the barrier layerwas remarkable. The durable repeating number was as shown below.

Having no barrier about 50 times Having a barrier about 700 timesExample 7 On an aluminum plate (31 microns thick), a conductive support,there was coated a mixture obtained by such a way that a 7 percent (byweight) solution of nitrocellulose (R840, trade name, supplied byDaiseru, degree of nitration 11.5 to 12.2 percent) was mixed with a 10percent solution of polyvinylpyrrolidone (PBP-K30, trade name, suppliedby GAF Co.) at ratio of 2:8 (by weight) both inethylalcohol-methylalcohol (7:3), and an amount of methyl ethyl ketone,which is a half of the resulting mixture by weight, was added to saidmixture, at 1 to 2 microns thick (when dried) to form a barrier layerand dried. This barrier layer had the same properties as those ofExample 5.

On the barrier layer, there was coated a photosensitive agent composedof poly-n-vinylcarbazole 2g., and Crystal Violet 10 mg, and Coumarone RS/2 (trade name, supplied by Fuji Seitetsu) as plasticizer in 40 ml. ofbenzene-chlorobenzene (1:1) to form a photosensitive layer of about 8microns thick. The resulting photosensitive plate was repeatedlysubjected to a process for transferring an electrostatic image to anelectrophotographic paper in a way similar to Example 5. The transferredelectrostatic latent image was developed with a toner by a magnet brushmethod. The discharge destruction preventing effect was remarkable, andfatigue phenomenon was very little and the durable repeating number wasas shown below.

Having no barrier layer about times Having a barrier layer about 1200times Example 8 A photosensitive plate prepared in a way similar toExample 7 was repeatedly subjected to a conventional xerographic processcomprising charging at -7.0 KV, exposing an image at lux. sec.,developing by a cascade method, transferring to an ordinary paper andcleaning the photosensitive plate. It was found that the dischargedestroy preventing effect was excellent. The durable repeating numberwas as shown below.

Having no barrier about 50 times Having a barrier about 700 timesExample 9 On a support as used in Example 5 there was coated, in l to 2microns thick when dried, a mixture obtained by such a way that a 12percent solution of nitrocellulose (SS %a, trade name, supplied byDaiseru, degree of nitration of 10.7 to 11.9 percent) inethylalcoholmethylalcohol (7:3) was mixed with a 10 percent solution ofpolyvinylpyrrolidone (PBP-90, trade name, supplied by GAF Co.) in thesame solvent as above, at ratio 7:3 (by weight), and amounts of methylethyl ketone and dimethylformamide each of which is one fourth the abovemixture by weight, respectively, was added to said mixture, to form abarrier layer and dried. The resulting barrier layer was highlytransparent, strong and flexible, and furthermore, could tightly adhereto an aluminum base plate. On the barrier layer there was coated aphotosensitive agent composed of 0.5 mole of chlorinatedpoly-N-vinylcarbazole 2 g., and 2,4,7-trinitrofluorenone 3.2 g., anddiphenyl chloride as plasticizer in 40 ml. of tetrahydrofuran to form aExample An electrophotosensitive plate as used in Example 9 wasrepeatedly subjected to a xerographic process comprising charging at-7.0 KV, imagewise exposing at about 20 lux. sec., developing by amagnet brush method, transferring to an ordinary paper, and cleaning thephotosensitive layer. The resulting image on the transferring paper wasclear, and there was hardly observed the discharge destruction. Thedurable repeating number was as shown below.

Having no barrier about 200 times Having a barrier about 3000 timesExample 1 I On a sandblasted aluminum plate (100 microns thick) as aconductive support there was coated, in l to 2 microns thick when dried,a mixture obtained by such a way that a 20 percent solution ofnitrocellulose (RS-l/4, trade name, supplied by Daiseru, degree ofnitration 11.5 to 12.2 percent) in a mixed solvent ofethylalcohol-methylalcohol (7:3) Was mixed with a 10 percent solution ofpolyvinylpyrrolidone (PEP-K90, trade name, supplied by GAF Co.) in thesame solvent as above, at the ratio 1:1 (by weight), and amounts ofmethyl ethyl ketone and dimethylformamide each of which is one fourththe above mixture by weight, respectively was added to said mixture, toform a barrier layer and dried. The resulting barrier layer was highlystrong and flexible, and furthermore, could tightly adhere to a support.On the barrier layer there was coated a photosensitive agent composed ofpoly-N vinylcarbazole 2 g., 2.4,5,7-tetranitrofluorenone 3.7 g., and 0.5g. of diphenyl chloride (trade name, Kanechlor) in 40 ml. oftetrahydrofuran in about microns thick when dried. This photosensitiveplate was repeatedly subjected to an electrostatic transferring methodcomprising charging at -7.0 KV, exposing to a light image at about 15lux. sec. and transferring to an electrostaticrecording paper. Theelectrostatic recording paper was developed with a liquid developer. Thedischarge destruction preventing effect was remarkably improved. Thedurable repeating number was as shown below.

8 Having no barrier layer about 250 times Having a barrier layer about3000 times Example 12 On a paper treated for imparting conductivity as aconductive support there was coated, in l to 2 microns thick when dried,a mixture obtained by such a way that a 10 percent solution ofnitrocellulose (RS 2, trade name, supplied by Daiseru, degree ofnitration of l 1.5 to 12.2 percent) in a mixed solvent ofethylalcoholmethylalcohol (7:3) was mixed with a 10 percent solution ofpolyvinylpyrrolidone (PBP-K60, trade name, supplied by GAF Co.) in thesame solvent as above, at ratio of 3:7 (by weight), and an amount ofmethyl ethyl ketone which is a half of the resulting mixture by weight,was added to said mixture, to form a barrier layer and dried. Theresulting barrier layer has film property similar to that of Example 5.On the barrier layer there was coated a photosensitive agent composed of0.5 mole of chlorinated poly-N-vinylcarbazole 2 g., and2,4,7-trinitrofluorenone 3.2 g., and 0.5 g. of diphenyl chloride as aplasticizer in 40 ml. of tetrahydrofuran at about 12 microns thick whendried.

The resulting photosensitive plate was repeatedly subjected to anelectrostatic transferring process comprising charging at 7.0 KV,exposing to a light image at about 5 lux. sec., and transferring to anelectrostatic recording paper. The electrostatic recording paper wasdeveloped by a magnet brush method to produce images of good quality.The discharge destruction preventing effect was also excellent. Thedurable repeating number was as shown below.

Having no barrier about 200 times Having a barrier about 4000 timesExample 1 3 On a conductive member composed of polyester film micronsthick) having an aluminum vapordeposited layer having a visible raytransmittance rate of 60 percent, there was coated, in l to 2 micronsthick when dried, a mixture obtained by such a way that a 6 percentsolution of nitrocellulose (RS-20, trade name, supplied by Daiseru,degree of nitration of l 1.5 to 12.2 percent) in a mixed solvent ofethylalcoholmethylalcohol (7:3) was mixed with a 10 percent solution ofpolyvinylpyrrolidone (PEP-K30, trade name, supplied by GAF Co.) in thesame solvent as above, at ratio of 1:1 (by weight), and an amount ofmethyl ethyl ketone which is one fourth the resulting mixture by weight,was added to said mixture, to form a barrier layer and dried. Thisbarrier layer had film property similar to that of Example 5. Further,on the barrier layer there was coated a photosensitive agent composed ofpoly-N-vinylcarbazole 2 g., Rhodamine B 20 mg., and diphenyl chloride asplasticizer in 40 ml. of benzene-chlorobenzene (1:1) to form aphotosensitive layer of 10 microns thick when dried.

The resulting photosensitive member was repeatedly subjected to anelectrostatic transferring method comprising charging at -7.0 KV,exposing a light image at about 50 lux. sec. and transferring to anelectrostatic recording paper. The electrostatic recording paper wasdeveloped with a liquid developer. The discharge destruction preventingeffect was remarkable.

Example 14 A 10 percent solution of nitrocellulose (RS-2, trade name,supplied by Daiseru, degree of nitration of 11.5 to 12.7 percent) inmethyl ethyl ketone-methyl isobutyl ketone (6:4) was mixed with apercent solution of polyvinylpyrrolidone (PEP-K90, trade name, suppliedby GAF Co.) in isopropanol-methanol (4:6) at ratio of 3:7 (by weight),and an amount of a mixed solvent of methyl ethylketone-dimethylformamide (1:1 which is a half of the resulting mixtureby weight, was added to said mixture to obtain a transparent and lowviscous liquid, as a solution for a barrier layer. Then, TiO was addedto the above liquid at ratio of resin solid to TiO- 6:1, ball-milled fortwo days and filtered to obtain a coating solution. On a polycarbonatelaminated support of aluminium foil therewas coated the resultingsolution in 5 to 4 microns thick when dried to form a white barrierlayer. The resulting coated film was highly strong adhesive and had agood hiding property.

Further, on the barrier layer there was coated a photosensitive agentcomposed of a solution of poly-N- vinylcarbazole, a trimethine dye, anda plasticizer such as Coumarone RS l/2, Coumarone LCR and chlorinatedparaffin in toluene-monochlorobenzene (1:1) in 5 to 6 g./m. when driedto form a photosensitive plate.

The resulting photosensitive plate was subjected to charging by a knownmethod and then loaded it in a conventional camera to take a photographof an upper half figure of a man by exposing to a strobolight at adistance of 15 m. Removing the photosensitive plate out of the camera ina dark room when finished to photograph, it was developed with a liquiddeveloper to obtain an excellent reflexion positive image of a man.

We claim:

1. An electrophotographic photosensitive member which comprises anelectrically conductive support, a barrier layer overlying theelectrically conductive support, the barrier layer comprising a blend ofnitrocellulose and polyvinylpyrrolidone in which the ratio ofnitrocellulose to polyvinylpyrrolidone is in the range of 2:8 to 8:2, byweight, and having a thickness of 1 to 10 microns and an organicphotoconductive layer overlying the barrier layer.

2. An electrophotographic photosensitive member according to claim 1 inwhich the organic photoconductive layer is composed of organic polymericphotoconductive material.

3. An electrophotographic photosensitive member according to claim 2 inwhich the organic polymeric photoconductive material is an organicphotoconductive material selected from the group consisting ofpoly-N-vinylcarbazole, chlorinated poly-N- vinylcarbazole, brominatedpoly-N-vinylcarbazole, cyanated poly-N-vinyl-carbazole, andpolyvinylacenaphthene.

1. AN ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MEMBER WHICH COMPRISES ANELECTRICALLY CONDUCTIVE SUPPORT, A BARRIER LAYER OVERLYING THEELECTRICALLY CONDUCTIVE SUPPORT, THE BARRIER LAYER COMPRISING A BLEND OFNITROCELLULOSE AND POLYVINYLPYRROLIDONE IS IN WJIHICH THE RATIO OFNITROCELLULOSE TO POLYVINYLPYRROLIDONE IS IN THE RANGE OF 2:8 TO 8:2, BYWEIGHT, AND HAVING A THICKNESS OF 1 TO 10 MICRONS AND AN ORGANICPHOTOCONDUCTIVE LAYER OVERLYING THE BARRIER LAYER.
 2. Anelectrophotographic photosensitive member according to claim 1 in whichthe organic photoconductive layer is composed of organic polymericphotoconductive material.
 3. An electrophotographic photosensitivemember according to claim 2 in which the organic polymericphotoconductive material is an organic photoconductive material selectedfrom the group consisting of poly-N-vinylcarbazole, chlorinatedpoly-N-vinylcarbazole, brominated poly-N-vinylcarbazole, cyanatedpoly-N-vinyl-carbazole, and polyvinylacenaphthene.